Arcane... is simply a spell not on the published Spell List of the Campaign Handbook.
A player has to have GM approval to use it in game; usually because its too scary, powerful, rare, ancient, deity-powered, dangerous, unique, wacky, or too newly created to see in the handbook.
Whole plots have been formed around such things... and thought it would be fun to document whatever we can remember for future fun.
So to any GM;s who can remember an arcane spell or to all Players who have made a "Special Stuff" request...
Lets try to get some of it listed!

please re-format as needed

Arcane Modifications to existing spells: Sometimes arcane spells are made by just modifying the description such as:
Continual Duration:
Range Extension: ("range of y)voice, line of sight", Area Affect instead of Touch)

Arcane Spells (or spell descriptions found on arcane objects):
Borrow (Corbae followers per GM)
Bind Soul
Charge Item (Enchanter Class Only)
Coercion
Collapse Ward
Control Mage
Elemental Gate/ Temporary Arch
Enchantments beyond Perfect (Enchanter Class Only)
Enhanced Magical Area
Ethereal Form
Explosion (Alchemical)
Hypnotic State - Mesmerize
Invoke (Enchanter Class Only)
Interrogate - answer one question truthfully or suffer as PAIN.
Levitate
Polymorph
Redirect
Splinter Wood
Shatter (Break Enchanted or Magically forged)
Void Life Area
Void Mage.

Arcane Fields of Study:
Rune Magic
Convoker
Enchanter (proposal)
Illusionist (proposal)

Arcane Items and its availability/contact:
Consortium Arch
Djinn Lamp (controling the Djinn Cabloz)
Godstone
Orb of Aldarion
Orb of Djinn Control
Statue of Galporis
Puzzle Amulet (http://xaria.wikispaces.com/Amulet+Puzzle)
Eye of Kreer
Tears of Baethus